In the light of evolution I: Adaptation and complex design

D arwin’s elucidation of natural selection as a creative evolutionary force was one of the monumental intellectual achievements in the history of science, not only revolutionizing thought across the biological sciences but also fundamentally impacting much discourse in the social sciences, philosophy, and religion. No longer were explanations for the origin and marvelous adaptations of organisms necessarily to be sought solely in the context of supernatural causation. Instead, biological outcomes could now be interpreted within the critical scientific framework of natural processes governed by natural processes and laws. As a young man, Charles Darwin (like most biologists of his era and before) was a natural theologian steeped in the notion that an attentive study of organisms in nature would ineluctably serve to document and further glorify the infinite creative powers of the Almighty. Darwin read and greatly admired William Paley’s 1802 Natural Theology, which eloquently developed the ‘‘argument from design’’ that biological complexity was prima facie evidence for an intelligent engineer. This age-old idea had an illustrious intellectual pedigree. For example, it had been one of the ‘‘Five Ways’’ that St. Thomas Aquinas (an influential Dominican scholar of the 13th century) purported to prove God’s existence. In 1779, the Scottish philosopher David Hume again encapsulated conventional wisdom when he wrote